Electronic metronome



Aug. 2, 1966 c. o. MUSSER ELECTRONIC METRONOME Filed May 7. 1965 FIG. 3.

INVENTOR.

C LA IR OMAE Muas z Eon A20 D. OER/AN A Tram/z Y United States Patent3,263,551 ELECTRONIC METRONOME (Ilair 0. Mussel", 12997 Blairwood Drive,Studio City, Calif.

Filed May 7, 1965, Ser. No. 454,026 4 Claims. (Cl. 84-484) Thisinvention is directed to an electric metronome, and particularly to ametronome which is capable of producing a clear tone of a predeterminednote and repeating the tone at a predetermined time rate.

Metronomes are well known in the musical art. Metronomes are arranged toprovide a series of audible signals at a predetermined time rate so asto aid a musician in keeping his musical rendition operating at aconstant rate. Metronomes are conventionally of an adjustable time rate,so that the musician may make the necessary adjustments to suit thecharacter of the piece he is rendering. The normal tone created by ametronome is a woody click which has no particular basic frequency andthus does not interfere with the musical tones rendered. Such metronomesmay be either mechanical or electronic, and a well known electronicmetronome is shown in Andersen Patent No. 2,522,492.

On certain occasions it becomes desirable to create a relatively puretone. This tone is used for tuning and can be used for checking theaccuracy of tone produced 'on those instruments which do not have everynote preestablished.

Accordingly, it is an object of this invention to provide a metronomewhich has a structure which produces a relatively pure tone.

It is another object of this invention to provide an electronicmetronome which is capable of periodically producing relatively puretones at a predetermined time rate.

It is a further object of this invention to provide means to excite atone bar independent of the striking thereof so that a more pure note isproduced by the tone bar.

Another object of this invention is to excite a tone bar byelectromagnetic inductionso as to avoid the physical striking of thetone bar to create a note therefrom, and to thereby create a more puretone, and produce a tone which does not change over a period of time dueto tone bar distortion due to' striking.

It is a further object of this invention to provide a resonance chamberin conjunction with a tone bar of relatively small dimensions so thatthe tone bar can be placed in a relatively limited space and so that theresonance chamber which is particularly designed for the primaryfrequency of the tone bar amplifies such a frequency so as to make thesound clearly audible.

Other objects and advantages of this invention will become apparent froma study of the following portion of the specification, the claims andthe attached drawings in which:

FIG. 1 is an isometric view of a metronome embodying the structure ofthis invention;

FIG. 2 is a slightly enlarged vertical section therethrough takengenerally along the line 22 of FIG. 1;

FIG. 3 is a partial, enlarged vertical section taken generally along theline 3-3 of FIG. 1; and

FIG. 4 is a schematic electrical circuit of a portion of the metronomeof this invention.

As an aid to understanding this invention itcan be stated in essentiallysummary form that it is directed to a metronome. In addition to themeans for creating normal conventional time spaced clicking sounds, themetronome is also provided with means for producing time spaced musicaltones.

The metronome is provided with an electronic timing device which issuitably adjustable so as to create ad- "ice instability of the outputsignal therefrom. The output signal is normally fixed at a predeterminedtime rate, which is predetermined by the adjustment. The output signalnormally drives a conventional clicker mechanism which produces theconventional audible signal for the metronome. The metronome of thisinvention is provided with a suitable selector switch so that the timedoutput electronic signal can alternatively be directed to a tone barexciting solenoid. Mounted within the. metronome is a conventional tonebar made of ferromagnetic material. The tone bar is mounted on itsquarter points and is provided with a suitable resonance chamber. Inview of the relatively confined space in which the tone bar is to belocated its size must be such that little amplitude is created at thedesired fundamental frequency thereof. Therefore, a resonance chamber,particularly designed for this fundamental frequency, is mounted inassociation with the tone bar so as to amplify the tone resulting fromtone bar actuation and make it clearly audible. Mounted directlyadjacent to and associated therewith is a solenoid coil whichelectromagnetically energizes the tone bar without physical contacttherewith. The previously described switch connects this solenoid to thepredetermined constant rate electronic signal. Thus, the tone bar isperiodically excited to produce its tone.

This invention will be understood in greater detail by reference to thefollowing portion of this specification where the drawings aredescribed. Referring now to FIG. 1, the metronome of this invention isgenerally indicated at 10. The metronome 10 has a housing 12 to enclosethe interior mechanism thereof and provide a framework structuretherefor. The housing 12 has a bottom 14, top 16, left and right walls18 and 20 as well as front 22 and a suitable rear closure.

Carried upon front 22 is adjustment knob 24 which is movable withrespect to indicia 26. Internal connections of the adjustment knobprovide suitable signal to the electronics housed in chassis 28 so thatthe chassis produces an output signal of the frequency adjusted by knob24 and indicated by indicia 26.

The electronic structure for producing the output signal of a frequencyin accordance with the adjustment, and the transducer which converts theelectronic signal to an audible signal is well known in the art. Such isapparent in Andersen Patent No. 2,522,492, granted September 19, 1950,the entire disclosure of which is incorporated herein by this reference.

As is best seen in FIG. 3, the conventional transducer structure forconverting the electronic signal to the audible signal comprisessolenoid coil 30 which is mounted by bracket 32 upon the top chassis2-8. Core 34 is fixedly mounted within the coil 30, and is arranged sothat upon energization of coil 30 ferromagnetic disc 36 is attracted byelectromagnetic attraction. Ferromagnetic disc 36 is mounted upon a thinwood diaphragm 38. Attraction causes mechanical contact with core 34 orwith ferromagnetic flux guide 39. Holes 40 in right wall 20 permit theclicking sound of the disc 36 striking core 34 to be audible from theoutside of metronome 10. If desired, bracket 32 can be made adjustablewith respect to chassis 28 so as to change the amount of deflectionrequired of dia phragm 38 for contact of disc 36 with core 34 and/ortude, but at the same time it definitely does not have any particulartonal value wherein a particular frequency and its overtones aredominant. Therefore, the tone of the clicker can be described as atonal.

Also mounted within housing 12 is solenoid coil 42. Coil 42 is mountedupon bracket 44 which is secured to the bottom of resonance chamber 46.The resonance chamber in turn is secured within housing 12.

Ferromagnetic tone bar 48 is mounted upon posts 50 and 52 which aresubstantially at the nodes of tone bar 48. By this mounting, tone bar 48is located in conjunction with the resonance chamber 46 which has aresonance opening 54 substantially adjacent the center of tone bar 48.Resonance chamber 46 is tuned to the tone of the tone bar to enhance itsaudio output. Furthermore, iron core 56 is located by this mountingstructure to be very closely adjacent to the tone bar 48 withoutcontacting it. However, core 56 is sufficiently close to the tone bar topermit the electromagnetic flux generated by coil 42 and directed by theiron of core 56 to act upon tone bar 48. The electromagnetic attractionis suflicient to bend the tone bar 48 to create a tone therefrom.

Tone bar 48 is preferably of such dimensions as to have a fundamentalfrequency in accordance with the international standard of 440 cyclesper second, which is the standard for the note A. In view of the limitedspace in which the tone bar 48 is situated, it must be of relativelyshort nature and thus must be relatively thin in order to haveafundamental frequency of 440 cycles. Since it is thin, the amplitude ofthe resulting compressive sound waves created in the adjacent air issuch that the tone is barely audible, or perhaps inaudible to theaverage human ear. In order to enhance the amplitude so as to make itclearly audible, resonance chamber 46 with opening '54 is employed. Theopening 54 is adjacent the maximum deflection point of tone bar 48 atits fundamental frequency so as to permit maximum actuation of the aircolumn within the resonance chamber. The resonance chamber is especiallydesigned so as to have adequate volume of air to be able to resonate atthe fundamental frequency, and still be of relatively limited size.Thus, the resonance chamber is able to amplify the signal created bytone bar 48 and produce a properly audible signal. In order to enhancethis signal openings 57 may be formed in the side 18.

Referring now to FIG. 4, chassis 28 is connected to a suitable supply ofelectric power. This may be an internal battery or it may be an externalsource of electric power. The output signal from the chassis 28 istransmitted by line 58 to single pole double throw switch 64. Contact 60is connected through signal line 66 to coil 30 and thence by line 68back to chassis 28. Further-more, contact 62 is connected by signal line70 to coil 42. Coil 42 is connected to line 68. Lamp 72 is mounted onthe top of housing 12 so as to be clearly visible from all sides. Lamp72 is connected between lines 58 and 68 so as to be operative wheneither the coil 30 or coil 42 is energized. It is clear that lamp 72 isoptional, and supplies a visual signal in conjunction with the clickeror tone signal.

It can thus be seen that when in operation, the periodic signalgenerated in line 58 passes through normally closed contact 60, whenswitch 64 is connected thereto, and thence through line 66, coil 30 andline 68 to cause pe riodic actuation of core 34. Thus, the periodicelectric signal in line 58 causes periodic motion of core 34 againstdisc 36 to make the conventional clicking sound. However, upon turningof switch 64, contact 60 is opened and the contact 62 is closed. Thus,the periodic signal in output line 58 passes through contact 62, line70, coil 42 and line 68, back to the chassis 28. When this occurs, theperiodic electrical signal causes deflection of tone bar 48 and thisdeflection in turn produces a periodically repeated tone.

It is more important to note that electromagnetic actuation of tone bar48 causes a more clear tone than the mechanical striking thereof so thata more clear tone is produced. The mechanical striking of a tone bar ortuning fork soon mechanically distorts it to a suflicient extent that itno longer produces a true tone. However, with the electromagneticactuation of tone bar 48, such is clearly not the case and a clear,accurate tone is produced for the full life of the metronome 10. Thistone is useful in tuning instruments and is useful in producing theperiodic tone signal necessary for good musical rendition.

This invention having been described in its preferred embodiment, it isclear that it is susceptible to numerous modifications and changeswithin the ability of those skilled in the art without the exercise ofthe inventive faculty. Accordingly, the scope of this invention isdefined by the scope of the following claims.

I claim:

1. An electronic metronome, said electronic metronome comprising:

a housing, an electronic signal generator positioned within saidhousing, and an audible sound producing device positioned within saidhousing;

said audible sound producing device comprising a solenoid having a coretherein, tone generating means mounted within said housing, said tonegenerating means being capable of being magnetically excited to producea substantially clear tone, said core being positioned adjacent'to saidtone generating means and out of contact therewith so that electricalenergization of said solenoid produces electro-magnetic force whichcauses deflection of said tone generating means to cause it to emit atone, said solenoid being connected to said electronic signal generator,said tone generating means being arranged to emit a substantially cleartone;

a resonance chamber mounted within said housing and adjacent said tonegenerating means so as to resonate the tone of said tone generatingmeans, said resonance chamber having an opening therein, said opening insaid resonance chamber being adjacent a portion of said tone generatingmeans which moves upon emission of an audible signal from said tonegenerating means, said resonance chamber being coupled with said tonegenerating means by means of an air column extending from said tonegenerating means through said opening in said resonance chamber and intosaid resonance chamber so that said tone generating means isnon-mechanically audibly coupled to said resonance chamber and saidresonance chamber amplifies the tonal sound of said tone generatingmeans.

2. An electronic metronome, said electronic metronome comprising:

a housing, an electronic signal generator, and first and second audiblesound producing devices;

said housing comprising at least a front wall and side wall;

said electronic signal producing device comprising an electronicchassis, adjustment means mounted upon said front wall of said housing,said adjustment means being electrically connected to said chassis, anelectric output line connected to said chassis, said chassis beingelectronically arranged to regularly periodically emit an electricsignal into said output line, said adjustment means connected to saidchassis being arranged to adjust the period of said electricalsignalinto said output line;

a manually operable selective switch connected to said output line, saidswitch having first and second signal lines connected thereto and beingarranged to selectively connect said first and second signal lines tosaid output line, so that said first and second signal lines areselectively energized by said output line;

said first audible sound producing device comprising a first solenoidhaving a core therein, said core being arranged to deflect a diaphragmupon energization of said first solenoid, said deflection being arrangedto produce an atonal audible signal, said first solenoid being connectedto said first signal line;

said second audible sound producing device comprising a second solenoidhaving a fixed core therein, and a tone bar mounted within said housing,said fixed 5 core being positioned adjacent said tone bar and out ofcontact therewith so that electrical energization of said secondsolenoid produces electromagnetic deflection of said tone bar to causeit to emit a tone, said second solenoid being connected to said secondsignal line, said tone bar being arranged to emit a substantially cleartone;

a resonance chamber mounted within said housing and adjacent said tonebar so as to resonate the tones of said tone bar, said tone bar beingcoupled to said resonance chamber by an air column so that when saidtone bar is actuated, compressed waves enter said resonance chamber andsaid resonance chamber amplifies said compressed waves so as to producea tonal amplified audible sound so that when said manual switch isconnected to energize said first signal line, an atonal periodic signalis produced and when said electric switch is connected to energize saidsecond signal line, a tonal signal is produced.

3. The electronic metronome of claim 2 wherein said tone bar is mountedat its quarter points and said resonance chamber has an opening thereinadjacent to the center of said tone bar.

4. An electronic metronome, said electronic metronome comprising:

a housing, an electronic signal generator positioned within saidhousing, and an audible sound producing device positioned within saidhousing;

said audible sound producing device comprising a solenoid having a fixedcore therein, a tone bar mounted 35 within said housing, said fixed corebeing positioned adjacent to said tone bar and out of contact there withso that electrical energization of said solenoid produceselectromagnetic force which causes deflection of said tone bar to causeit to emit a tone, said solenoid being connected to said electronicsignal generator, said tone bar being arranged to emit a substantiallyclear tone;

a resonance chamber mounted within said housing and adjacent said tonebar so as to resonate the tones in said tone bar, said resonance chamberhaving an opening therein, said opening in said resonance chamber beingadjacent a portion of said tone bar which moves upon emission of anaudible signal from said tone bar, said resonance chamber being coupledwith said tone bar by means of an air column extending from said tonebar, through said opening in said resonance chamber and into saidresonance chamber so that said tone bar is non-mechanically audiblycoupled to said resonance chamber and said resonance chamber amplifiesthe total sound of said tone bar.

References Cited by the Examiner UNITED STATES PATENTS 1,930,997 10/1933Fascinato 58-130 2,152,177 3/1939 Eisenbeis et a1. 84-454 2,307,1041/1943 Bossard 84-410 X 2,522,492 9/ 1950 Andersen 58130 X 3,038,1206/1962 Bernstein et a1. 58130 X LOUIS J. CAPOZI, Primary Examiner.

STEPHEN I. TOMSKY, LEO SMILOW, Examiners.

1. AN ELECTRONIC METRONOME, SAID ELECTRONIC METRONOME COMPRISING: AHOUSING, AN ELECTRONIC SIGNAL GENERATOR POSITIONED WITHIN SAID HOUSING,AND AN AUDIBLE SOUND PRODUCING DEVICE POSITIONED WITHIN SAID HOUSING;SAID AUDIBLE SOUND PRODUCING DEVICE COMPRISING A SOLENOID HAVING A CORETHEREIN, TONE GENERATING MEANS MOUNTED WITHIN SAID HOUSING, SAID TONEGENERATING MEANS BEING CAPABLE OF BEING MAGNETICALLY EXCITED TO PRODUCEA SUBSTANTIALLY CLEAR TONE, SAID CORE BEING POSITIONED ADJACENT TO SAIDTONE GENERATING MEANS AND OUT OF CONTACT THEREWITH SO THAT ELECTRICALENERGIZATION OF SAID SOLENOID PRODUCES ELECTRO-MAGNETIC FORCE WHICHCAUSES DEFLECTION OF SAID TONE GENERATING MEANS TO CAUSE IT TO EMIT ATONE, SAID SOLENOID BEING CONNECTED TO SAID ELECTRONIC SIGNAL GENERATOR,SAID TONE GENERATING MEANS BEING ARRANGED TO EMIT A SUBSTANTIALLY CLEARTONE; A RESONANCE CHAMBER MOUNTED WITHIN SAID HOUSING AND ADJACENT SAIDTONE GENERATING MEANS SO AS TO RESONATE THE TONE OF SAID TONE GENERATINGMEANS, SAID RESONANCE CHAMBER HAVING AN OPENING THEREIN, SAID OPENING INSAID RESONANCE CHAMBER BEING ADJACENT A PORTION OF SAID TONE GENERATINGMEANS WHICH MOVES UPON EMISSION OF AN AUDIBLE SIGNAL FROM SAID TONEGENERATING MEANS, SAID RESONANCE CHAMBER BEING COUPLED WITH SAID TONEGENERATING MEANS BY MEANS OF AN AIR COLUMN EXTENDING FROM SAID TONEGENERATING MEANS THROUGH SAID OPENING IN SAID RESONANCE CHAMBER AND INTOSAID RESONANCE CHAMBER SO THAT SAID TONE GENERATING MEANS ISNON-MECHANICALLY AUDIBLY COUPLED TO SAID RESONANCE CHAMBER AND SAIDRESONANCE CHAMBER AMPLIFIES THE TONAL SOUND OF SAID TONE GENERATINGMEANS.